Thermometer



' www Feb., 25, 3936,

A, E. WHITTHER THERMOMETER Filed March l2, 1935 @wf i" f Patented Feb.25, 1936 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to thermometers of the mechanical class, that is,thermometers in which the temperature indicating means is actuated by acoiled thermo-responsive metallic strip.

The object of the invention is the provision of a simple, compact,sensitive, and accurate thermometer of the class mentioned which willshow individual degree readings in large gures and that is particularlyadapted for application to the doors and walls of stove and range ovenswhich are heated by gas, coal, oil or electricity, but that is alsocapable of use in other locations.

This object is attained by arranging the temperature indicating figureson a rotatably mounted cylinder that encircles a coil of thermostaticmetal, one end of the coil being attached to the cylinder and the otherend of the coil being adjustably fastened to a member which is fixed inan enclosing case that in front of the cylinder has a window designed toexpose but one temperature reading at a time.

In the accompanying drawing the invention is illustrated as designed foran oven thermometer.

Fig. 1 shows a front view of the thermometer.

Fig. 2 shows a rear View with a part of the case removed.

Fig. 3 shows a section on the plane indicated by the dotted line 3--3 onFig. 2.

Fig. 4 shows a section on the plane indicated by the dotted line 4 4 onFig. 2.

Fig. 5 shows a section on the plane indicated by the dotted line 5-5 onFig. 2.

The enclosing case of the oven thermometer shown comprises a threadedshell I which is open at both ends and that has an external flange 2 andinternal flange 3 at the front end, and a threaded shell #l which has aclosed rear end and an external flange 5 at its front end, the formershell being adapted to be thrust into an opening in a wall or panel andthe latter shell tol be screwed upon the former shell in such mannerthat the Wall or panel will be clamped between the external flanges ofthe shells.

In the front end of the shell I is a disk 6 that has a window I and inthe construction illustrated this disk has ears 8, 9, bent in fromdiametrically These ears are perforated and Rotatably mounted on thespindle near the ear 8 is a collar Extending in from and fastened to theear (Cl. 'I3-118) 9 is a hub I2. Rotatably mounted upon this hub butdesigned to be fastened thereto by a screw I3 is a collar I4. Acylindrical member I5 upon which temperature indicating figures orlettering are arranged so as t0 read longitudinally of the axis of thecylinder, is fastened by screws I6 to the rotatable collar I I. One endof a strip I'I of thermostatic metal coiled within the cylindricalmember is fastened by a screw I8 to the collar I I. The other end of thethermostatic coil is fastened by a screw I9 to the collar I 4. Byloosening the screw I3 and turning the collar I4 the tension of the coilmay be adjusted for the purpose of Calibrating the elements in orderthat the gures will show the correct temperature through the window 'Iin the shell.

With the active elements properly calibrated figures showing the correcttemperature to which the thermometer is subjected Will be seen throughthe window in the closure. But one temperature reading at a time isexposed through this window. Owing to the length of the coil ofthermo-responsive metal which is arranged in a small space in thisstructure, extended angular movements of the cylinder are attained asthe temperature changes. This permits close calibration and allows thegures to be so large that they may be quickly read without effort orclose inspection.

The invention claimed is:-

l. A thermometer comprising a shell that is open at both ends, aremovable disk closing one end of said shell, said disk having a window,a cylindrical member rotatable in the shell and carrying temperatureindications adapted to be exposed through said window, and a coil ofthermo-responsive metal with one end connected to said disk and theother end connected to the cylindrical member.

2. A thermometer comprising a shell, a disk with a window at one end ofthe shell, said disk having inwardly extending ears, a spindle looselysupported by said ears, a cylindrical member rotatably mounted in theshell upon said spindle and carrying temperature indications adapted tobe exposed through said window, and a coil of thermo-responsive metalwith one end fixed with relation to the shell and the other end attachedto said cylindrical member.

ALBERT E. WHITTIER.

